Add 1 ½ tbsp. vegetable oil to a heated pan. Add 6 medium sized chopped tomatoes, 1 medium sized onion chopped, 3 serrano peppers chopped fine, 1 garlic clove mince ans 2 tbsp of chopped cilantro. Cook for a minute. Add a tbsp. ketchup, 1 tbsp hot sauce (Valentino) and 1 tbsp lime juice, Mix. Add ½ ib shrimp , ½ tsp salt and ½ tsp oregano. Mix and remove the pan. Heat another flat-bottomed pan and place 2 tacos. Place half of tomato mix and 1 ½ tbsp grated cheese on in each. Fold over once the bottom has browned. Take the tacos way and serve hot with Mexican rice.